1. Field of the Invention
The present invention relates to a process for production of 2-acetylbenzo[b]thiophene, which is useful as an intermediate for the synthesis of an antiinflammatory agent, Zileuton.
2. Related Art
As a process for production of 2-acetylbenzo[b]thiophene, a process comprising reacting benzo[b]thiophene with a strong base such as butyl lithium, followed by reaction with acetylchloride is described in J. Chem. Soc. Comun., 3447 (1977). In this process, however, the reaction with butyllithium must be carried out at a low temperature and therefore an operation is industrially difficult, and moreover the starting material, benzo[b]thiophene is expensive.
Comptes rendus, vol. 234, 736 describes a process for production of 2-acetylbenzo[b]thiophene by reacting 2-mercaptobenzaldehyde with chloroacetone. However, in this process, the starting material, 2-mercaptobenzaldehyde is difficult to synthesize, and unstable, and therefore handling the same is not convenient.